Door engine



Patented Jan. 21, 1930 UNITED STATESv ,PATENT orifice JOSEPH M. DAPRON, OF ST. LOUIS, MISSOURI, ASSIGNOB.` TO NATIONAL PNEUMATIC COMPANY, OF NEW YORK, N. VY., A .CORPORATION OF WEST VIRGINIA Doon ENGIE Application filed December 15, 1923'. Serial No. 681,023.

My invention relates to improvements in' door engines and has fror'its ob]ect to provide a pneumatic engine consisting of a cylinderA having a median longitudinal slot, a double headed piston mounted in said cylinder and having a central arm extending through said slot; and a single slidable rod member axially mounted through said piston. Said slidable rod member may also have the capacity of ado justabilityI as to its length.

` Drawings The drawing' is a longitudinal mid-sectional view of an engine embodying my i11- vention.`

Description The cylinder A is formed of the halves 1 and 2 and has the. median slot 3, and heads 4 and 5 in which air-pipes 6 and 7 are cen- .25 freely to atmosphere.

13 formed on its surface.

trally mounted, each head. having an inwardly extending valve seat 8. The pipes 6 and 7 are so valve-controlled that when one is being used as an inlet the other is 'exhausted The pipes 6 and 71 are connected by an ordinary two-way valve 30 to a source'of fluid pressure through pipe marked Pressure This valve also has the exhaust outlet marked 0 Exhaust I Within the cylinder A isthe double-headed piston B havingthe heads 9 and 10 and the axial bore 11 through which extends the rod l12 having the longitudinal air-vent or groove l Each of said heads 9 and 10 has a bushing 14 with an outwardly-extending valve seat 15.

The rod 12 carries at each end a pair of valve disks 16-*16 mounted bv means of a screw 17 and adjustably spaced from the rod 12 by a series of washers 18 whose number may beincreased or diminished to alte lengthof the shock-absorbing element.

l midway its length, and actuates the operating shaft 20 through 4the connecting rod 21 and Mode of operation The drawing shows the piston-arm 19 at the left end of'its stroke, with the left-hand outer-disk 16` in contact with and closing the valve seat 8 on the head 4. To move the piston-arm 19 air is admitted through the pipe 6 behind piston 9 by turning valve 30 so as to connect pipe 6 with the pressure source, driving the disk 16 out 'of contact with said lefthand nipple 8, when the pressure will strike the left-hand cupped `washer 23. The rod 12 and piston B will continue to move in unison mtil the right hand disk 16 strikes and seats against the right-hand valve seat 8, sealing 'the air space at the right of the piston-headlO to form an air-cushion K(the piston B continuing by force of its momentum and the /pressure behind it to move to theright while the rod'12 is stationary). As soon as the disk 16 contacts with the valve seat 8, the cylinder 2 is cut olf'from exhaust and the pressure in z begin t slow down and when the pressure in cylinde 1 and2 becomes eoualized. the pistons become stationary. This i's a gradual process so that the door or device connected to shaft -20.is brought to a gradual stop.

Itfis of course evident that the relativepositions of pistons 9 -and 10 may be adjusted so that disks 16 may or may not rest on seats 15 at the end of the stroke. secured by rotating the threaded screw 17 into or outo rod 12 the necessary distance. By this meansvmthe pistons can-'be stopped `at any predetermined point in their travel.

Aswarioiisfrjembodiments maybe made in lThis adjustment is the invention above set forth and as many said bore having two spaced chan es might be made in the structure hereinbe ore described, it is to be understood that all matter herein set forth is to be interpreted as illustrative and not in a limiting sense.

vI claim 1. In an engine the combination with a cylinder havin-g a double headed piston mounted at opposite ends of a connecting rod, said pistons and rod having an axial bore extending entirely through them of means in said bore extending from both ends of the connecting rod for effecting the cushioning of the pistons near the end of their stroke in Aeither direction.

2. In an engine the combination with a cylinder having a double headed piston mounted at opposite ends of a connecting rod, said pistons and rod having an axial bore of means in said bore extending from both ends of the connecting rod for cushioning the pistons near the 'en of their stroke in either direction and fluid pressure connections for each end of the cylinder having control means for admitting Huid pressure to either end of the cylinder.

3. In an engine the combinationfwith a cylinder having a double headed' piston mounted at opposite ends of a connecting rod, said istons and rod having an axial bore of slida ly mounted means in and thrpughout the length of said bore and projecting beyond each end of the connecting rod to admit fluid pressure throu h said bore from the-working end of the cyllnder to the other end of the cylinder to cushion the piston when said slidably mounted means engages the end of the cylinder towards which the iston is moving.

4. In an engine the com ination with a cylinder having a double headed piston mounted at opposite ends of a connecting rod, said pistons and rod having an axial bore of a rod mounted in said bore of a length greater than the iston assembly and means on said rod to adIinit fluid pressure into the opposite end of the cylinder from the working end to cushion the piston stroke.

5. In an engine the'r combination with a cylinder having a double headed piston mounted at opposite ends of a connecting rod, said pistons and rod having an axial bore of a grooved rod slidabl mounted in 'sks mounted on each end, said rod bein longer than the piston assembly and said 'sks cooperating with said pistons and the ends of the cylinder to admit fluid pressure to the exhausting end of the cylinder to cushion the pistons.

6. In an engine the combination with a cylinder having a double headed piston' mounted at opposite ends of a connecting rod, said pistons and rod having an axial bore, of slidable means in said bore to cut o' the cylinder exhaust and admit uid pressure from the working end to the other end of the cylinder to cushion the pistons.

7. In an engine the comblnatlon wlth a cylinder having double headed piston assem-' 

